Field of the Invention
The present invention relates generally to an organic light emitting diode (OLED) display and a manufacturing method thereof.
Description of the Related Art
An organic light emitting device includes two electrodes and an organic light emitting layer interposed therebetween. One of the two electrodes injects holes and the other injects electrons into the light emitting layer. The injected electrons and holes are combined to form excitons and the excitons emit light as discharge energy.
Among methods of forming red, green and blue emission layers to realize full color of the organic light emitting diode (OLED) display, there is a laser induced thermal imaging using a laser.
In laser induced thermal imaging, a laser beam generated from a laser beam generator is patterned by using a mask pattern, and the patterned laser beam is irradiated on a donor film, including a base film and a transfer layer, to expand and to transfer a portion of the transfer layer to the organic light emitting diode (OLED) display, thereby forming an emission layer for the organic light emitting diode (OLED) display. As a result, there are advantages in that each emission layer may be precisely patterned, and the laser induced thermal imaging is a dry process.
The transfer layer is made of a single layer of the organic emission layer or a dual layer of the organic emission layer and a resonance assistance layer, and when the transfer layer is made to the single layer of the organic emission layer, thermal energy is transmitted to a hole transport layer (HTL) in the laser induced thermal imaging process such that a carrier accumulation is generated in an interface between the hole transport layer (HTL) and the organic emission layer, and thereby a characteristic of the organic light emitting element may be deteriorated.
Also, when the transfer layer is made of the dual layer of the organic emission layer and the resonance assistance layer, performance of the interface between the resonance assistance layer and the organic emission layer is improved, but the carrier accumulation is generated in the interface between the hole transport layer (HTL) and the organic emission layer such that the characteristic of the organic light emitting element may be deteriorated.
Also, thermal damage to the resonance assistance layer and the hole transport layer (HTL) is serious because of the thermal energy generated when using the laser induced thermal imaging such that the driving voltage may be excessively increased.
Also, when using the laser induced thermal imaging, heat is transmitted to the anode such that the interface characteristic between the anode and the hole injection layer (HIL) may be deteriorated.
The above information disclosed in this Background section is only for enhancement of an understanding of the background of the described technology, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.